body{
  height: 100vh;
  overflow: hidden;
}

#app{
  display: flex;
  align-items: center;
  justify-content: center;
  height: 100%;
}

.app_bg{
  position: absolute;
  top: -20px;
  bottom: -20px;
  left: -20px;
  right: -20px;
  background: url(https://images.unsplash.com/photo-1556745757-8d76bdb6984b) no-repeat center/cover;
  filter: blur(20px);
  z-index: -1;
}

.form{
  background-color: #fff;
  width: 500px;
  border-radius: 10px;
  padding: 30px;
  text-align: center;
  color: #333;
}
.form-container{
  
}

.title{
  font-weight: 700;
  font-size: 30px;
}
.subtitle{
  margin-top: 3px;
  font-size: 16px;
  color: #999;
}
.form-item{
  text-align: left;
  margin-top: 20px;
}
.form-label{
  font-size: 16px;
  margin-bottom: 10px;
  font-weight: 500;
}

.form-input input{
  height: 40px;
  width: 100%;
  border-radius: 5px;
  border: 1px solid #ccc;
  padding-left: 10px;
  color: #333;
  font-size: 16px;
}

.form-input input::placeholder{
  color: #aaa;
}

.sub_btn{
  position: relative;
  background-color: #000;
  color: #fff;
  font-size: 16px;
  font-weight: 700;
  height: 40px;
  line-height: 40px;
  border-radius: 5px;
  cursor: pointer;
  margin-top: 30px;
  overflow: hidden;
}

.ripple{
  width: 10px;
  height: 10px;
  background-color: rgba(255, 255, 255, .5);
  position: absolute;
  left: 0;
  top: 0;
  transform: translate(-50%,-50%);
  border-radius: 50%;
  animation: spread .5s linear;
}

@keyframes spread{
  0%{
    transform: translate(-50%,-50%) scale(1);
  }
  100%{
    transform: translate(-50%, -50%) scale(100);
  }
}